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Frequently Asked Questions (FAQs)

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Why do carbon dioxide emissions weigh more than the fuel they originated from?

The amount of carbon dioxide (CO2) produced from burning fuel weighs more than the fuel does. During complete combustion, each carbon atom in the fuel combines with two oxygen atoms in the air to make CO2. CO2  has an atomic weight of 44—about 3.6667 times the atomic weight of carbon, which is 12.

For example, subbituminous coal is, on average, 51% carbon. So, the carbon in a short ton (2,000 pounds) of subbituminous coal weighs 1,020 pounds. The CO2 emissions from burning a short ton of subbituminous coal weigh approximately 3,740 pounds, or about 3.67 times the weight of the carbon and 1.87 times the weight of the coal.

Learn more:
Atomic weights of all elements in the periodic table of elements.
How much carbon dioxide is produced when different fuels are burned?

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